Removal from core mold part of tubular injection molded plastic product formed with two open ends

ABSTRACT

A hollow plastic product with a substantially tubular section, two open ends and a thread at the outside of one end of the product is removed from a core mold part by closing the threaded end of the molded product and injecting compressed air into the molded product to loosen the molded product from the core mold part. The threaded end of the product is closed by attaching a closure having a matching thread onto the threaded end.

CROSS-REFERENCE TO RELATED APPLICATION

This is a divisional of co-pending application Ser. No. 10/813,970 filedMar. 31, 2004.

BACKGROUND OF THE INVENTION

The present invention generally pertains to injection molding of plasticproducts and is particularly directed to removal from a core mold partof a hollow injection molded product having a substantially tubularsection that is formed in the mold cavity with two open ends.

One process of manufacturing a hollow plastic product with asubstantially tubular section includes the steps of:

(a) providing a cavity mold part with a generally cylindrical portionfor forming at least an outside segment of the substantially tubularsection of the product;

(b) providing a core mold part with a generally cylindrical portion forforming at least an inside segment of the substantially tubular sectionof the product;

(c) combining the cavity mold part with the core mold part to configurea mold cavity for forming a product with a substantially tubularsection;

(d) injecting plastic material into the mold cavity to form the moldedplastic product; and

(e) separating the core mold part from the cavity mold part whileretaining the molded product on the core mold part; and

(f) removing the molded product from the core mold part.

It is difficult to remove a molded product with a substantially tubularsection from the core mold part because the injected plastic materialshrinks upon cooling within the mold cavity and thereby causes thesubstantially tubular section of the molded product to adhere tightly tothe generally cylindrical portion of the core mold part. Such difficultyis especially severe when the tubular section of the molded product isvery thin and flexible.

It is known in the prior art to inject compressed air into aninjection-molded hollow plastic product that is formed in the moldcavity with a substantially tubular section, one open end and one closedend in order to loosen the product from the core mold part.

SUMMARY OF THE INVENTION

The present invention provides a process of removing an injection-moldedhollow plastic product with a substantially tubular section, two openends and a thread at the outside of one end of the product from a coremold part, the process comprising the steps of:

(a) closing the threaded end of the molded product; and

(b) injecting compressed air into the molded product to loosen themolded product from the core mold part.

Additional features of the present invention are described withreference to the detailed description of the preferred embodiments. Someof these additional inventive features that are not claimed herein arereserved for divisional patent applications.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a partial sectional view of a mold in which cavity and coremold parts are combined for configuring a mold cavity in accordance withone preferred embodiment of the present invention, with the mold cavitybeing shown as configured at the commencement of injection of theplastic material.

FIG. 2 is an end view of the right end of the core mold part shown inFIG. 1.

FIG. 3 is a partial sectional view of the mold of FIG. 1, with the moldcavity being shown as reconfigured for injection of plastic materialduring an early portion of the injection cycle while the core mold partis being centered within the cavity mold part.

FIG. 4 is a partial sectional view of the mold of FIG. 1, with the moldcavity being shown as configured for further injection of plasticmaterial.

FIG. 5 is a partial sectional view of the mold of FIG. 1, with the moldcavity being shown as reconfigured by retraction of the inner core priorto separation of the core mold part from the cavity mold part after theplastic product has been molded in the mold cavity.

FIG. 6 is a partial view of the core mold part shown in FIG. 1 after thecore mold part has been separated from the cavity mold part whileretaining the molded product on the core mold part, wherein the innercore is still retracted when compressed air is initially injected tohelp remove the product from the core mold part.

FIG. 7 is a partial view of the core mold part subsequent to the viewshown in FIG. 6 wherein the inner core is protracted to further helpremove the molded product from the core mold part and compressed air isfurther injected to still further help remove the product from the coremold part.

FIG. 8 is a plan view of one preferred embodiment of an injection-moldedproduct manufactured in accordance with the present invention.

FIG. 9 is a partial sectional view of a mold in which cavity and coremold parts are combined for configuring a mold cavity in accordance withanother preferred embodiment of the present invention, with the moldcavity being shown as configured prior to commencement of injection ofthe plastic material.

FIG. 10 is an end view of the right end of the core mold part shown inFIG. 9.

FIG. 11 is a partial sectional view of the mold of FIG. 9, with the moldcavity being shown as reconfigured for injection of plastic materialduring an early portion of the injection cycle while the core mold partis being centered within the cavity mold part.

FIG. 11A is an enlarged view of the portion of FIG. 11 shown withincircle 11A.

FIG. 12 is a partial sectional view of the mold of FIG. 9, with the moldcavity being shown as reconfigured for further injection of plasticmaterial.

FIG. 13 is a partial sectional view of the mold of FIG. 9, with the moldcavity being shown as reconfigured for still further injection ofplastic material to form the closed end of the molded product.

FIG. 14 is a partial sectional view of the mold of FIG. 9, with the moldcavity being shown as reconfigured by retraction of the inner core priorto separation of the core mold part from the cavity mold part after theplastic product has been molded in the mold cavity.

FIG. 15 is a partial view of the core mold part shown in FIG. 9 afterthe core mold part has been separated from the cavity mold part whileretaining the molded product on the core mold part, wherein the innercore is still retracted when compressed air is initially injected tohelp remove the product from the core mold part.

FIG. 16 is a partial view of the core mold part subsequent to the viewshown in FIG. 15, wherein the inner core is protracted to further helpremove the molded product from the core mold part and compressed air isfurther injected to still further help remove the product from the coremold part.

FIG. 17 is a partial sectional view of a mold in which cavity and coremold parts are combined for configuring a mold cavity in accordance withstill another preferred embodiment of the present invention, with themold cavity being shown as configured prior to commencement of injectionof the plastic material.

FIG. 18 is an end view of the right end of the core mold part shown inFIG. 17.

FIG. 19 is a partial sectional view of the mold of FIG. 17, with themold cavity being shown as reconfigured for injection of plasticmaterial during an early portion of the injection cycle while the coremold part is being centered within the cavity mold part.

FIG. 20 is a partial sectional view of the mold of FIG. 17, with themold cavity being shown as reconfigured for further injection of plasticmaterial.

FIG. 21 is a partial sectional view of the mold of FIG. 17, with themold cavity being shown as reconfigured for still further injection ofplastic material to form the closed end of the molded product.

FIG. 22 is a partial sectional view of the mold of FIG. 17, with themold cavity being shown as reconfigured by retraction of the inner coreprior to separation of the core mold part from the cavity mold partafter the plastic product has been molded in the mold cavity.

FIG. 23 is a partial view of the core mold part shown in FIG. 17 afterthe core mold part has been separated from the cavity mold part whileretaining the molded product on the core mold part, wherein the innercore is still retracted when compressed air is initially injected tohelp remove the product from the core mold part.

FIG. 24 is a partial view of the core mold part subsequent to the viewshown in FIG. 23 wherein the inner core is protracted to further helpremove the molded product from the core mold part and compressed air isfurther injected to still further help remove the product from the coremold part.

FIGS. 25 to 30 illustrate a process of removing an injection-moldedhollow plastic product with a substantially tubular section, two openends and a thread at the outside of one end of the product from a coremold part in accordance with the other aspect of the present invention.

DETAILED DESCRIPTION

One preferred embodiment of the present invention is described withreference to FIGS. 1 to 7. A mold 10 includes a cavity mold part 12 anda core mold part 14, which are combined for configuring a mold cavity16. The mold cavity 16 is configured and reconfigured during differentstages of the manufacturing process to have different shapes and sizes.The core mold part 14 includes an inner core 18 and an outer core 20.The inner core 18 and the outer core 20 are independently movable withrespect to each other and with respect to the cavity mold part 12.

The cavity mold part 12 is combined with the core mold part 14 as shownin FIGS. 3 and 4 to configure and reconfigure the mold cavity 16 forforming a molded product hollow plastic product 22 with a substantiallytubular thin-wall section 24, one open end 26, one closed end 27 and athread 28 at the outside of the closed end 27 of the molded product 22,as shown in FIGS. 5-7. The portion of the mold cavity 16 that forms theopen end 26 of the molded product 22 is located between the outer core20 and a section 31 of the core mold part 14.

The cavity mold part 12 includes a generally cylindrical portion 30 forforming at least an outside segment of the substantially tubular section24 of the molded product 22, a thread-forming portion 32 for forming thethread 28 on the outside of a neck 29 of the molded product 22, ashoulder-forming portion 33 for forming the outside of a shoulder 34extending between the substantially tubular section 24 and the neck 29of the molded product 22 and a conical end portion 36 for forming theoutside of the closed end 27 of the molded product 22.

The outer core 20 of the core mold part 14 includes a generallycylindrical portion 38 for forming at least an inside segment of thesubstantially tubular section 24 of the product 22 and ashoulder-forming portion 39 for forming the outside of the shoulder 34.

The inner core 18 of the core mold part 14 includes a generallycylindrical portion 40 for forming the inside of the neck 29 of themolded product 22 lying inside the thread 28 and a conical end portion42 for forming the inside of the closed end 27 of the molded product 22.The inner core 18 forms the inside of the neck 29 and the inside of theclosed end 27 when the inner core 18 is almost fully protracted, asshown in FIGS. 3 and 4.

The mold cavity 16 also includes a plurality of flow leaders 44extending radially from a gate 45 and a plurality of flow guides 46. Theflow guides 46 are disposed for directing injected plastic material intoa thin-wall portion of the mold cavity 16 that forms the substantiallytubular thin-wall section 24 of the product 22. In this embodiment, thethin-wall section 24 of the product may be injection molded in themanner described in U.S. Pat. No. 6,599,460, the disclosure of which isincorporated herein by reference thereto.

At the commencement of injection of plastic material from an injectionunit (not shown), the inner core 18 and the outer core 20 are fullyprotracted to configure the mold cavity 16 as shown in FIG. 1 in orderto block flow of the plastic material within the mold cavity 16 andthereby compress the injected plastic material within the injection unitand the runner system (not shown) so that injection of the plasticmaterial into the thin-wall section of the mold cavity 16 is faster whensuch blockage is ended by partially withdrawing the inner core 18.

When the injected plastic material is suitably compressed, the innercore 18 is partially withdrawn to the protracted position shown in FIG.3 to enable the injected plastic material to flow within the mold cavity16 to form the closed end 27 and the neck 29 of the molded product 22,and to flow through the flow leaders 44 to the flow guides 46 and thenceto the other end of the mold cavity 16 that forms the open end 26 of themolded product 22 to thereby form the substantially tubular section 24of the molded product 22.

The outer core 20 remains fully protracted in contact with the cavitymold part 12 to thereby stabilize the core mold part 14 with respect tothe cavity mold part in order to control the position of the core moldpart 14 within the cavity mold part 12 and thereby the thickness of thesubstantially tubular section 24 of the molded product 22. In thisembodiment, the inner core 18 and the outer core 20 may be retracted andprotracted by hydraulic means and/or in the manner described in U.S.Pat. No. 4,867,672, the disclosure of which is incorporated herein byreference thereto.

When the substantially tubular section 24 of the molded product 22 hasbeen formed, the outer core 20 is retracted as shown in FIG. 4 to enablethe injected plastic material to flow within the mold cavity 16 to formthe shoulder 34 and thereupon complete the formation of the moldedproduct 22.

The molded product 22 is then allowed to cool within the mold cavity 16prior to removing the molded product 22 from the mold 10.

When the molded product 22 has cooled for a suitable duration, the innercore 18 is retracted as shown in FIG. 5 so that when the molded product22 is removed from the cavity mold part 12, the neck 29 is compressed bythe thread 28 to partially occupy the region of the mold cavity 16vacated upon removal of the inner core 18, whereby the thread 28 may beremoved from the cavity mold part 12 without damaging the thread 28.

After the inner core 18 has been retracted, the core mold part 14 isseparated from the cavity mold part 12 as shown in FIG. 6 to therebyremove the molded product 22 from the cavity mold part 12 whileretaining the molded product 22 on the core mold part 14. In oneversion, but not all versions, of this embodiment, compressed air isinjected between the molded product 22 and the cavity mold part 12 toloosen the molded product 22 from the cavity mold part 12 and therebyhelp the removal of the molded product 22 from the cavity mold part 12.The compressed air is injected through a channel 48 in one section 50 ofthe cavity mold part and thence through an air gap 51 of approximately0.01 mm between two sections 50, 52 of the cavity mold part 12.

Upon the molded product 22 being removed from the cavity mold part 12, arobotically operated product receiver (not shown) is moved intopositions between the cavity mold part 12 and the core mold part 14 toreceive the molded product 22 when the molded product is removed fromthe core mold part 14.

Compressed air is injected through the core mold part 14 into the closedend 27 of the molded product 22 to thereby at least help remove themolded product 22 from the core mold part 14.

Referring to FIG. 6, the compressed air is first injected through anouter channel 54 in the outer core 20. Because the end 27 of the moldedproduct 22 is closed and the open end 26 is also closed by reason ofbeing contained within the portion of the mold cavity 16 located betweenthe outer core 20 and the section 31 of the core mold part 14, theinitial injection of compressed air into the closed end 27 causes thesubstantially tubular section 24 to tend to balloon away from the coremold part 14 and thereby at least helps remove the molded product 22from the core mold part 14.

Referring to FIG. 7, the inner core 18 is then protracted in relation tothe outer core 20 to push against the neck 29 and as to increase thepressure within the closed end 27 to further help remove the moldedproduct 22 from the core mold part 14 when such further help isnecessary. Upon such protraction of the inner core 18 the inner channel56 is opened, whereupon the compressed air is injected through the innerchannel 56 into the closed end 27 to thereby still further help removethe molded product 22 from the core mold part 14.

After the molded product 22 has been removed from the core mold part 14,at least a portion of the closed end 27 is removed to thereby providethe molded product 22 with a substantially tubular section 24, a neck 29at one end 27 a and two open ends 26, 27 a, as shown in FIG. 8.

Another preferred embodiment of the present invention is described withreference to FIGS. 9 to 16. A mold 60 includes a cavity mold part 62 anda core mold part 64, which are combined for configuring a mold cavity66. The mold cavity 66 is configured and reconfigured during differentstages of the manufacturing process to have different shapes and sizes.The core mold part 64 includes an inner core 68 and an outer core 70.The inner core 68 and the outer core 70 are independently movable withrespect to each other and with respect to the cavity mold part 62.

The cavity mold part 62 is combined with the core mold part 64 as shownin FIGS. 11 to 13 to configure and reconfigure the mold cavity 66 forforming a molded product hollow plastic product 72 with a substantiallytubular thin-wall section 74, one open end 76, one closed end 77 and athread 78 at the outside of the closed end 77 of the molded product 72,as shown in FIGS. 14-16. The portion of the mold cavity 66 that formsthe open end 76 of the molded product 72 is located between the outercore 70 and a section 81 of the core mold part 64.

The cavity mold part 62 includes a generally cylindrical portion 80 forforming at least an outside segment of the substantially tubular section74 of the molded product 72, a thread-forming portion 82 for forming thethread 78 on the outside of a neck 79 of the molded product 72, ashoulder-forming portion 83 for forming the outside of a shoulder 84extending between the substantially tubular section 74 and the neck 79of the molded product 72 and a conical end portion 86 for forming theoutside of the closed end 77 of the molded product 72.

The outer core 70 of the core mold part 64 includes a generallycylindrical portion 88 for forming at least an inside segment of thesubstantially tubular section 74 of the product 72 and ashoulder-forming portion 89 for forming the outside of the shoulder 84.

The inner core 68 of the core mold part 64 includes a generallycylindrical portion 90 for forming the inside of the neck 79 of themolded product 72 lying inside the thread 78 and a conical end portion92 for forming the inside of the closed end 77 of the molded product 72.The inner core 68 forms the inside of the neck 79 and the inside of theclosed end 77 when the inner core 68 is protracted, as shown in FIGS. 11and 12.

The mold cavity 66 also includes a plurality of flow leaders 93extending radially from a gate 94, a plurality of circular throttles 95and a plurality of flow guides 96. The flow guides 96 are disposed fordirecting injected plastic material into a thin-wall portion of the moldcavity 66 that forms the substantially tubular thin-wall section 74 ofthe product 72. In this preferred embodiment, the thin-wall section 74of the product may be injection molded in the manner described in U.S.Pat. No. 6,599,460.

At the commencement of injection of plastic material from an injectionunit (not shown), the inner core 68 and the outer core 70 are fullyprotracted to configure the mold cavity 66 as shown in FIG. 9 in orderto block flow of the plastic material within the mold cavity 66 andthereby compress the injected plastic material within the injection unitand the runner system (not shown) so that injection of the plasticmaterial into the thin-wall section of the thin-wall section of the moldcavity 66 is faster when such blockage is ended by partially withdrawingthe inner core 68.

When the injected plastic material is suitably compressed, the outercore 70 is partially withdrawn as shown in FIGS. 11 and 11A to enablethe injected plastic material to flow through the flow leaders 93 intothe neck-forming portion of the mold cavity 66 to form the neck 79 ofthe molded product 72, thence into the shoulder-forming portion of themold cavity 66 to begin formation of the shoulder 84 and thence to theflow guides 96, which direct the injected plastic material to the otherend of the mold cavity 66 that forms the open end 76 of the moldedproduct 72 to thereby form the substantially tubular section 74 of themolded product 72. The inner core 68 remains fully protracted in contactwith the cavity mold part 62. The partial withdrawal of the outer core70 is to a position 0.2 mm from the fully protracted position shown inFIG. 9. In this embodiment, the inner core 18 and the outer core 20 maybe retracted and protracted by hydraulic means and/or in the mannerdescribed in U.S. Pat. No. 4,867,672.

The flow of the injected plastic material through the flow leaders 93 tothe flow guides 96 is throttled by the throttles 95 to control theposition of the core mold part 64 within the cavity mold part 62 in amanner similar to that described in U.S. Pat. No. 4,959,005 withreference to FIGS. 1 and 2 therein and thereby controls the thickness ofthe substantially tubular section 74 of the molded product 72. Therelevant disclosure of U.S. Pat. No. 4,959,005 is incorporated herein byreference thereto.

When the substantially tubular section 74 of the molded product 72 hasbeen formed, the outer core 70 is retracted as shown in FIG. 12 toenable the injected plastic material flowing within the mold cavity 66to complete formation of the shoulder 84, and the inner core 68 ispartially withdrawn to the protracted position shown in FIG. 13 toenable the injected plastic material flowing within the mold cavity 66to form the closed end 77 of the molded product 72, and thereuponcomplete the formation of the molded product 72. The retraction of theouter core 70 is to a position 1.0 mm from the fully protracted positionshown in FIG. 9.

Although the retraction of the outer core 70 is shown in FIG. 12 asoccurring before the partial withdrawal of inner core 68, in alternativeversions of this embodiment the retraction of the outer core 70 mayoccur after or simultaneously with the partial withdrawal of inner core68.

The molded product 72 is then allowed to cool within the mold cavity 66prior to removing the molded product 72 from the mold 60.

When the molded product 72 has cooled for a suitable duration, the innercore 68 is retracted as shown in FIG. 13 so that when the molded product72 is removed from the cavity mold part 62, the neck 79 is compressed bythe thread 78 to partially occupy the region of the mold cavity 66vacated upon removal of the inner core 68, whereby the thread may beremoved from the cavity mold part 62 without damaging the thread 78.

After the inner core 68 has been retracted, the core mold part 64 isseparated from the cavity mold part 62 as shown in FIG. 14 to therebyremove the molded product 72 from the cavity mold part 62 whileretaining the molded product 72 on the core mold part 64. In oneversion, but not all versions, of this embodiment, compressed air isinjected between the molded product 72 and the cavity mold part 62 toloosen the molded product 72 from the cavity mold part 62 and therebyhelp the removal of the molded product 72 from the cavity mold part 62.The compressed air is injected through a channel 98 in one section 100of the cavity mold part and thence through an air gap 101 ofapproximately 0.01 mm between two sections 100, 102 of the cavity moldpart 72.

Upon the molded product 72 being removed from the cavity mold part 62, arobotically operated product receiver (not shown) is moved intopositions between the cavity mold part 62 and the core mold part 64 toreceive the molded product 72 when the molded product is removed fromthe core mold part 64.

Compressed air is injected through the core mold part 64 into the closedend 77 of the molded product 72 to thereby at least help remove themolded product 72 from the core mold part 64.

Referring to FIG. 15, the compressed air is first injected through anouter channel 104 in the outer core 70. Because the end 77 of the moldedproduct 72 is closed and the open end 76 is also closed by reason ofbeing contained within the portion of the mold cavity 76 located betweenthe outer core 70 and the section 81 of the core mold part 64, theinitial injection of compressed air into the closed end 77 causes thesubstantially tubular section 74 to tend to balloon away from the coremold part 64 and thereby at least helps remove the molded product 72from the core mold part 64.

Referring to FIG. 16, the inner core 68 is then protracted in relationto the outer core 70 to push against the neck 79 and as to increase thepressure within the closed end 77 to further help remove the moldedproduct 72 from the core mold part 64 when such further help isnecessary. Upon such protraction of the inner core 68 the inner channel106 is opened, whereupon the compressed air is injected through theinner channel 106 into the closed end 77 to thereby still further helpremove the molded product 72 from the core mold part 64.

After the molded product 72 has been removed from the core mold part 64,at least a portion of the closed end 77 is removed to thereby providethe molded product with a substantially tubular section, a neck at oneend and two open ends, as shown in FIG. 8.

Another preferred embodiment of the present invention is described withreference to FIGS. 17 to 24. A mold 110 includes a cavity mold part 112and a core mold part 114, which are combined for configuring a moldcavity 116. The mold cavity 116 is configured and reconfigured duringdifferent stages of the manufacturing process to have different shapesand sizes.

The core mold part 114 includes an inner core 118 and an outer core 120.The inner core 118 and the outer core 120 are independently movable withrespect to each other and with respect to the cavity mold part 112.

The cavity mold part 112 is combined with the core mold part 114 asshown in FIGS. 19 to 21 to configure and reconfigure the mold cavity 116for forming a molded product hollow plastic product 122 with asubstantially tubular thin-wall section 124, one open end 126, oneclosed end 127 and a thread 128 at the outside of the closed end 127 ofthe molded product 122, as shown in FIGS. 20-24. The portion of the moldcavity 116 that forms the open end 126 of the molded product 122 islocated between the outer core 120 and a section 131 of the core moldpart 114.

The cavity mold part 112 includes a generally cylindrical portion 130for forming at least an outside segment of the substantially tubularsection 124 of the molded product 122, a thread-forming portion 132 forforming the thread 128 on the outside of a neck 129 of the moldedproduct 122, a shoulder-forming portion 133 for forming the outside of ashoulder 134 extending between the substantially tubular section 124 andthe neck 129 of the molded product 122 and a conical end portion 136 forforming the outside of the closed end 127 of the molded product 122.

The outer core 120 of the core mold part 114 includes a generallycylindrical portion 138 for forming at least an inside segment of thesubstantially tubular section 124 of the product 122 and ashoulder-forming portion 139 for forming the outside of the shoulder134.

The inner core 118 of the core mold part 114 includes a generallycylindrical portion 140 for forming the inside of the neck 129 of themolded product 122 lying inside the thread 128 and a conical end portion142 for forming the inside of the closed end 127 of the molded product122. The inner core 118 forms the inside of the neck 129 and the insideof the closed end 127 when the inner core 118 is protracted, as shown inFIGS. 19 and 20.

The mold cavity 116 also includes a plurality of flow leaders 143extending radially from a gate 144, a plurality of spiral flow leaders145 and a plurality of flow guides 146. The flow guides 146 are disposedfor directing injected plastic material into a thin-wall portion of themold cavity 116 that forms the substantially tubular thin-wall section124 of the product 122. In this preferred embodiment, the thin-wallsection 124 of the product may be injection molded in the mannerdescribed in U.S. Pat. No. 6,599,460.

At the commencement of injection of plastic material from an injectionunit (not shown), the inner core 118 and the outer core 120 are fullyprotracted to configure the mold cavity 116 as shown in FIG. 17 in orderto block flow of the plastic material within the mold cavity 116 andthereby compress the injected plastic material within the injection unitand the runner system (not shown) so that injection of the plasticmaterial into the thin-wall section of the mold cavity 116 is fasterwhen such blockage is ended by partially withdrawing the inner core 118.

When the injected plastic material is suitably compressed, the outercore 120 is partially withdrawn as shown in FIG. 19 to enable theinjected plastic material to flow through the radial flow leaders 143into the neck-forming portion of the mold cavity 116 to form the neck129 of the molded product 122, thence through the spiral flow leaders145 into the shoulder-forming portion of the mold cavity 116 to beginformation of the shoulder 134 and thence to the flow guides 146, whichdirect the injected plastic material to the other end of the mold cavity116 that forms the open end 126 of the molded product 122 to therebyform the substantially tubular section 124 of the molded product 122.The inner core 118 remains fully protracted in contact with the cavitymold part 112. The partial withdrawal of the outer core 120 is to aposition 0.2 mm from the fully protracted position shown in FIG. 17. Inthis embodiment, the inner core 18 and the outer core 20 may beretracted and protracted by hydraulic means and/or in the mannerdescribed in U.S. Pat. No. 4,867,672.

The flow of the injected plastic material through the radial flowleaders 143 to the flow guides 146 controls the position of the coremold part 114 within the cavity mold part 112 in a manner similar tothat described in U.S. Pat. No. 4,959,005 with reference to FIGS. 5 and6 therein to thereby control the thickness of the substantially tubularsection 124 of the molded product 122. The relevant disclosure of U.S.Pat. No. 4,959,005 is incorporated herein by reference thereto.

When the substantially tubular section 124 of the molded product 122 hasbeen formed, the outer core 120 is retracted as shown in FIG. 20 toenable the injected plastic material flowing within the mold cavity 116to complete formation of the shoulder 134, and the inner core 118 ispartially withdrawn to the protracted position shown in FIG. 21 toenable the injected plastic material flowing within the mold cavity 116to form the closed end 127 of the molded product 122, and thereuponcomplete the formation of the molded product 122. The retraction of theouter core 120 is to a position 1.0 mm from the fully protractedposition shown in FIG. 17.

Although the retraction of the outer core 120 is shown in FIG. 20 asoccurring before the partial withdrawal of inner core 118, inalternative versions of this embodiment the retraction of the outer core120 may occur after or simultaneously with the partial withdrawal ofinner core 118.

The molded product 122 is then allowed to cool within the mold cavity116 prior to removing the molded product 122 from the mold 110.

When the molded product 122 has cooled for a suitable duration, theinner core 118 is retracted as shown in FIG. 21 so that when the moldedproduct 122 is removed from the cavity mold part 112, the neck 129 iscompressed by the thread 128 to partially occupy the region of the moldcavity 116 vacated upon removal of the inner core 118, whereby thethread 128 may be removed from the cavity mold part 112 without damagingthe thread 128.

After the inner core 118 has been retracted, the core mold part 114 isseparated from the cavity mold part 112 as shown in FIG. 22 to therebyremove the molded product 122 from the cavity mold part 112 whileretaining the molded product 122 on the core mold part 114. In oneversion, but not all versions, of this embodiment, compressed air isinjected between the molded product 122 and the cavity mold part 112 toloosen the molded product 122 from the cavity mold part 112 and therebyhelp the removal of the molded product 122 from the cavity mold part112. The compressed air is injected through a channel 148 in one section150 of the cavity mold part and thence through an air gap 101 ofapproximately 0.01 mm between two sections 150, 152 of the cavity moldpart 122.

Upon the molded product 122 being removed from the cavity mold part 112,a robotically operated product receiver (not shown) is moved intopositions between the cavity mold part 112 and the core mold part 114 toreceive the molded product 122 when the molded product is removed fromthe core mold part 114.

Compressed air is injected through the core mold part 114 into theclosed end 127 of the molded product 122 to thereby at least help removethe molded product 122 from the core mold part 114.

Referring to FIG. 23, the compressed air is first injected through anouter channel 154 in the outer core 120. Because the end 127 of themolded product 122 is closed and the open end 126 is also closed byreason of being contained within the portion of the mold cavity 116located between the outer core 120 and the section 131 of the core moldpart 114, the initial injection of compressed air into the closed end127 causes the substantially tubular section 124 to tend to balloon awayfrom the core mold part 114 and thereby at least helps remove the moldedproduct 122 from the core mold part 114.

Referring to FIG. 24, the inner core 118 is then protracted in relationto the outer core 120 to push against the neck 129 and as to increasethe pressure within the closed end 127 to further help remove the moldedproduct 122 from the core mold part 114 when such further help isnecessary. Upon such protraction of the inner core 118 the inner channel156 is opened, whereupon the compressed air is injected through theinner channel 156 into the closed end 127 to thereby still further helpremove the molded product 122 from the core mold part 114.

After the molded product 122 has been removed from the core mold part114, at least a portion of the closed end 127 is removed to therebyprovide the molded product with a substantially tubular section, a neckat one end and two open ends, as shown in FIG. 8.

The preferred plastic material used for injection molding the product ispolypropylene. Alternatively other plastic materials may be so used.

In alternative embodiments, (a) the mold cavity is not blocked in orderto compress the injected plastic material within the injection unit andthe runner system prior to injecting the plastic material into thethin-wall section of the mold cavity, as described with reference toFIGS. 1, 9 and 17, (b) the inner core is not protracted during removalof the molded product from the core mold part, as shown in FIGS. 7, 16and 24 and/or (c) the molded product may have many different shapesother than the shape illustrated herein.

A preferred embodiment of a process of removing an injection-moldedhollow plastic product 200 with a substantially tubular section 202, twoopen ends 204, 206 and a thread 208 at the outside of one end 206 of theproduct 200 from a core mold part 210 is described with reference toFIGS. 25-30. The product 200 may be molded in a manner similar to themolding of the products in the embodiments described above withreference to FIGS. 1-24, with some modifications.

The mold includes a core mold part 210 and a cavity mold part 212, whichare combined to configure and reconfigure a mold cavity in which theproduct 200 is formed. The core mold part 210 includes an outer core 214and an inner core 216, as in the above-described embodiments. However,the core mold part 216 is modified to include a center core 218 within asleeve 220. The outer core 214, the center core 218 and the sleeve 220are movable with respect to one another and with respect to the cavitymold part 212. The core mold part also includes inner and/or outerchannels 221 through which compressed air can be injected to help removethe molded product 200 from the core mold part 210.

Although the product 200 is shown as having been molded with a closedend member 222 having a different shape than the conical closed end ofthe molded product in the above-described embodiments, in an alternativeembodiment, the closed end member 222 of the product 200 may be conicalor still some other shape. The molded product 200 may have manydifferent shapes other than the shape illustrated herein.

The cavity mold part 212 is modified to include an ejector plate 224that is separable from a cavity plate 226 located at the end of the moldcavity part 212 that forms the outside of the threaded end 206 of theproduct 200. The ejector plate 224 is combined with a runner plate 228.

The configuration of the mold upon the completion of the molding cycleis illustrated in FIG. 25.

Referring to FIG. 26, the center core 218 is protracted while theejector plate 224 and the runner plate 228 are separated from the cavityplate 226 to remove the closed end member 222 from the molded product200 to thereby provide the molded product 200 with two open ends 204,206. The removed closed end member 222 is momentarily retained by theejector plate 224.

After the core mold part 210 has been separated from the cavity moldpart 212 to separate the molded product 200 from the cavity mold part212 while retaining the molded product on the core mold part 210, asshown in FIG. 27, a first robotic arm 230 is moved into a positionbetween the molded product 200 and the cavity mold part 212 and a secondrobotic arm 232 is moved into a position between the ejector plate 224and the cavity plate 226. Preferably the first robotic arm 230 and thesecond 232 are coupled to a common robotic component (not shown), areoperated robotically, and are moved simultaneously into their respectivepositions.

The first robotic arm 230 includes a holder 233 for retaining a closure234 having a thread 236 matching the thread 208 at the threaded end 206of the product. Preferably the closure 234 is threaded plastic cap forthe product 200. The first robotic arm 230 also includes a port 240 forconnection to a compressed air source (not shown).

The second robotic arm 232 includes a chamber 242 for receiving theremoved closed end member 222 from the ejector plate 224 and a port 244for connection to a suction device (not shown).

Referring to FIG. 28, the first robotic arm 230 is moved toward themolded product 200 retained on the core mold part 210 in order tosqueeze the closure 234 onto the thread 208 of the molded product 200and thereby closes the threaded end 206 of the molded product 200. Atapproximately the same time, the removed closed end member 222 togetherwith a cold sprue attached thereto are removed from the ejector plate224 and the runner plate 228 by suction and are received in the chamber242.

Referring to FIG. 29, compressed air is injected through the channels221 into the molded product 200 in the manner described above withreference to FIGS. 6, 15 and 23 to loosen the molded product 200 fromthe core mold part 210 and the first robotic arm 230 is moved away fromthe core mold part 210 to remove the molded product 200 from the coremold part 210.

Referring to FIG. 30, the first robotic arm 230 is withdrawn from theposition between the core mold part 210 and the cavity mold part 212 andthe second robotic arm 232 is moved from the position between theejector plate 224 and the cavity plate 226. The first robotic arm 230thereby transfers the molded product 200 with the closure 234 attachedthereto from the position between the core mold part 210 and the cavitymold part 212. The closure 234 may be retained on the product 200 whilethe product is filled with some substance and until after the open end204 of the product 200 is closed.

In one preferred embodiment the closure is a plastic cap that isinjection molded in the injection molding system in which the product200 is injection molded. The plastic caps are injection molded at thesame average rate as the products 200 are injection molded. In oneinjection molding cycle a first robotic arm 230 acquires a plastic cap234 in the holder 233; and in the next injection molding cycle the firstrobotic arm pushes the closure 234 onto the threaded end 206 of aproduct 200.

In an alternative embodiment, the first robotic arm 230 includes aclosure that includes a thread, such as the thread 236, but which can beopened to the port 240. In this embodiment, the closure is pushed ontothe thread 208 at the threaded end 206 of the product 200 by moving thefirst robotic arm 230 toward the molded product 200 retained on the coremold part 214, as described with reference to FIG. 28, to thereby closethe threaded end 206 of the product 200. When compressed air is injectedinto the product 200 through the channels 221, as described withreference to FIG. 29, compressed air also is injected into the product200 through the port 240 in the first robotic arm 230 to help loosen themolded product 200 from the core mold part 210; and the first roboticarm 230 is moved away from the core mold part 210 to remove the moldedproduct 200 from the core mold part 210.

The processes and apparatus described herein can be used advantageouslywith the injection-molding and other processes and apparatus describedin U.S. Pat. Nos. 5,879,613; 5,858,286; 5,262,112; 5,149,482; 5,008,064;5,174,941 and 4,846,483 and U.S. patent application Ser. No. 10/715,618,filed Nov. 18, 2003.

The documents that are incorporated herein by reference thereto do notnecessarily use the same terminology as used herein.

The benefits specifically stated herein do not necessarily apply toevery conceivable embodiment of the present invention. Further, suchstated benefits of the present invention are only examples and shouldnot be construed as the only benefits of the present invention.

While the above disclosure contains many specificities that may or maynot be common to all of the embodiments described herein, thesespecificities are not to be construed as limitations on the scope of thepresent invention, but rather as examples of the preferred embodimentsdescribed herein. Other variations are possible and the scope of thepresent invention should be determined not by the embodiments describedherein but rather by the claims and their legal equivalents. The claimsrequire no implicit limitations. Each claim is to be construedexplicitly as stated, or by its legal equivalent.

Regarding the process claims, except for those steps that can only occurin the sequence in which they are recited, and except for those stepsfor which the occurrence of a given sequence is specifically recited ormust be inferred, the steps of the process claims do not have to occurin the sequence in which they are recited.

1. A process of removing an injection-molded hollow plastic product witha substantially tubular section, two open ends and a thread at theoutside of one end of the product from a core mold part, the processcomprising the steps of: (a) closing the threaded end of the moldedproduct; and (b) injecting compressed air into the molded product toloosen the molded product from the core mold part.
 2. A processaccording to claim 1, wherein step (a) comprises the step of: (c)attaching a closure having a matching thread onto the threaded end ofthe product.
 3. A process according to claim 2, wherein step (c)comprises the step of: (d) robotically using a robotic arm to attach thethreaded closure onto the threaded end of the product.
 4. A processaccording to claim 3, wherein the robotic arm includes the threadedclosure.
 5. A process according to claim 2, wherein the threaded closureis a plastic cap.
 6. A process according to claim 5, further comprisingthe step of: (d) injection molding the plastic cap in the injectionmolding system in which the product is injection molded.
 7. A processaccording to claim 6, wherein step (d) comprising the step of: (e)injection molding plastic caps at the same average rate as the productsare injection molded.